Method of making and enameling automobile bodies



Feb. 3, 1925. 1,525,009

5. SMITH METHOD OF MAKING AND ENAMELING AUTOMOBILE BODIES Filed Aug. 2, 1919 INVENTOR. w ZW y ATTORNEYS.

also Patented Feb. 3, 1925.

UNETED STAT-ES SYDNEY SMITH, or DETROIT, vrrcnrcan,

assrenoa. To THE STUDEBAKER. coaro a- TION, A CORPORATION Ol,NEW JERSEY.

METHOD OF MAKING AND ENAMELING AUTOMOBILE BODIES.

Application filed August 2, 19 19.

To all whom it may concern:

Be it known that I, SYDNEY SMITH, a citizen of the United States of America, and resident of Detroit, in the county of Wayne and State of Michigan, have invented certain new and useful Improvements in Methods of Making and Enamelin Automobile Bodies, of which the following is a specification.

This invention consists in a method of process by which automobile bodies may be constructed with a wooden frame and a metallic sheathing and an enamel coating or finish applied to the sheathing, said finish being treated by the application of heat, i. e. what is known as the baking operation. It also embraces the resultant article of manufacture.

Automobile bodies are usually constructed by first building up a frame work of wood, and then overlaying said framework with metal sheathing bent and formed to fit over the wooden frame. The sheathing is then treated with a suitable finish. It has long been recognized that the most lustrous, as well as the most durable finish, is that known to the trade as the baked finish, which results from the application of a plurality of coats of enamel subjected to a baking process. During the carrying out of this process, however, the, temperature required to properly bake the enamel is usually in the neighborhood of 300 F'., and, when it is endeavored to impart a baked finish toan automobile body, it is found that this temperature is so excessive that the wooden frame is very seriously affected. Heretofore, attempts to this end have resulted in so depreciating the wood of the frame that it became charred, warped, twisted and distorted and the glue by which the parts of the frame were united melted, with the result that the frame was loose jointed and squeaked and rattled when a vehicle thus manufactured was put to subsequent use.

For these reasons it has been considered. impractical to provide a car'body with the baked finish, through the inability of the wooden elements thereof to withstand the heat required. As a compromise it has been the usual practice, in car finishing to finish such all-metallic parts as the fenders, mud guards, etc. wit-h the'baked finish, i. e. em-

ploying saidprocess wherever possible on Serial No. 315,034.

all-metallic parts, and to finish the body, where this process had proven impractical, with the well-known float process, which consists in successively applying fluid coatings and permitting the same to dry. A car thus finished appears very attractive and neat when new and those parts of the car which have received the baked finish retain their attractive appearance for a long time, but the parts of the car which had been treated with the float process, rapidly deteriorate, lose their luster, and are highly sensitive to scratches so that, in a relatively short time, the body of such a car will appear dull and unsightly, while the all-metallic parts which have received the baked finish, will retain their luster. Another disadvantage inherent in the employment of the float process is the question of cost, it being well recognized that the fioat process, besides being much inferior to the baked finish is much more costly. In spite of these considerations, however, it is the common practice at the present time to employ, as a compromise, the combination of both processes in the manufacture ofautomobiles.

I have been involved in experimentation and research in an endeavor to discover 'a method whereby the superior baked finish might be applied to car bodies without deleterious efiects on the wooden frame thereof and, as a result I have found that if the wooden frame of the body is treated according to a certain process prior to the application of the enamel baking process, it may be so conditioned as to properly withstand the relatively high temperatures required in the carrying out of said baking process, and that the body portion of the automobile may thereafter be dealt with during the finishing operation in substantially the same manner as the all-metallic parts of the car without suffering ill effects due to theapplication ofthe baking heat.

The-process of treating wood in such manner as to adapt itito this. us forms the subject-inatter of my co-pending application, Serial No. 315035 filed Aug. 2nd, 1919, whereinthe consecutive st-ep's'in the carrying out jofthe method are set forth in detail and it is not considered necessary to reiterate the process .here. The method of this invention does not consist in the treatment o'f' the wood but is' direct ed ,rather to I the manufacture of automobile bodies through the fabrication of a frame treated in the manner described in my co-pending application, the application of sheathing to such a frame, and the subsequent finishing of the whole.

The accompanying drawings illustrate the manner in which a well known form of automobile body frame may be prepared for treatment by the method of this invention.

In carrying out the method of this invention in one of its practical forms, the wooden elements 1 of the frame are cut to shape and size and assembled in the usual way. This assembly may be carried out through the employment of bolts and screws 2 suplemented by glue but, if desired, the

glue may be omitted. If glue is employed, I prefer to use a glue which is especially prepared to possess such qualities that, when once set or hardened, it will not re spond, or be affected by heat. Of course, different kinds of glue may be employed, but I have found that ordinary hot glue proves quite satisfactory if there is added thereto a small quantity of bi-chromate of potash crystals and a little water. The glue is heated, and the crystals added whereupon the glue is immediately applied while hot, since such glue, when cold, is permanently set or hardened. The parts of the frame are thus glued together and the glue is preferably reinforced by screws or bolts so that at the conclusion of this step in the process the frame is complete in itself and is in the form to receive the sheathing.

After the framing operations are com pleted as described temporary braces 3 are preferably secured across the door openings in order that the frame may be held in proper shape during the successive operations thereon and these braces are preferably so positioned that they may be left in place during the paneling and finishing operations. The braces referred to, while an assistance, are not, however, essential and may be dispensed with without departing from this invention.

The frame assembled as described is now subjected to the treatment described in my co-pending application, which conditions the completed frame to be capable of with standing temperatures of the baked finish process without deterioration. If desired, the wooden elements of the frame may be treated before assembling them to form the frame. At the conclusion of the treatment on the completed frame the wooden elements thereof may be found to have contracted slightly and it is desirable at this stage, that the screws and bolts 2 thereof be gone over and taken up to compensate for any slight contraction which may have occurred. The sheathing is now applied to In carrying out the finishing operation good results are obtained by first washing the body thoroughly with gasoline and sanding the high spots with fine emory' cloth. Both the inside and outside may then be flowed with Oxford Low Baking Primer or any other suitable primer, and the whole baked for approximately an hour at 300 F. For second and third and subsequent coats any suitable finishing enamel maybe applied, each coat being baked for an hour at about the same temperature, al-

though the last coat should be baked sligh ly longer. This specific procedure has been found to give good results, although the present invention is manifestly not restricted to the details enumerated, as different temperatures and coatings may be employed and any number of these coatings may be applied as desired, in accordance with the finish sought. The body treated and finished as specified possesses all of the advantages of the baked finish as regards its luster and durability and the frame of said body remains firm and rigid and has tight joints. Char-rin deterioration, or alteration of the wood and frame does not occur and actual employment of the process condition under the hard usage of the road.

Having thus fully described the invention, what I claim as new and desire to secure by Letters Patent is:

1. In the art of automobile body making, the method which consists-in fitting together and assembling wooden frame elements and securing them in position by mechanical means, thereafter treating the wood of the assembled frame in such manner as to raise the heat resisting qualities of the wood to a point where it will withstand the heat necessary for imparting a baked finish to a metal sheathing to be subsequently applied thereto, and then tightening the mechanical means, to take up the contraction resulting from said treatment.

2. In the art of automobile body making, the method which consists in assembling wooden frame elements through the employment of a heat resisting glue and mechanical means to form a body frame,

thereafter treating the Wood of the assembled frame in such manner as to raise the heat resisting qualities of the wood to a point where it will withstand the heat necessary for imparting a baked finish to a metal sheathing, and finally tightening the mechanical means to take up the contraction resulting from such treatment.

3. In the art of automobile body making, the method which consists in assembling frame elements through the employment of glue and mechanical compression means to form a body frame, thereafter treating the wooden elements of the assembled frame to raise the heat resisting qualities thereof, then tightening said compression means to compensate for contraction in the frame during the treatment thereof, thereafter applying a metal sheathing to the thus treated frame and finally applying a baked finish thereto.

l. In the art of automobile body making, the method which consists of assembling frame elements through the employment of glue and mechanical compression means to form a body frame, thereafter treating said frame thus assembled in a manner to raise the heat resisting quality of the Wood of which it is composed, and tightening said mechanical compression means to compensate for contractions in said frame during said treatment thereafter applying a metal sheathing to said frame and treating said sheating with an enamel coating, and applying heat to such enameled coating of a suflicient degree to the same.

5. A new article of manufacture comprising an automobile body frame consisting of wooden elements united by glue in terposed between the contacting faces there of, said wooden elements being so treated by the application of enamel and heat as to raise the same to a high point of heat resistance, the said wooden frame being then subjected to mechanical pressure to compensate for contraction during the op eration of said last mentioned process.

6. A new article of manufacture comprising an automobile body frame consisting of wooden elements united by glue interposed between the contacting faces thereof, said wooden elements being so treated by the application of enamel and heat as to raise the same to a high point of heat resistance, the said wooden frame being then subjected to mechanical pressure to compensate for contraction during the operation of said last mentioned process, said frame being enclosed in a sheathing of metal finished with enamel treated by a baking process.

Signed by me at Detroit, Michigan, U. S. A., this 29th day of July, 1919.

SYDNEY SMITH. Witnesses VINCENT LINK, A. E. LEACH. 

